FastSort Manual

Optimizing Sort Performance
FastSort Manual—429834-003
9-8
Using a Partitioned Scratch File
Using a Partitioned Scratch File
A partitioned scratch file is a single scratch file partitioned across multiple disk
volumes. The multiple volumes can exist on separate nodes. A partitioned scratch file
functions in essentially the same manner during a sort operation as multiple scratch
files. While the maximum size of a nonpartitioned scratch file is 1 TB if it is created by
the user and up to 2 GB otherwise, a partitioned scratch file can be greater than 1 TB.
Partitioned scratch files are especially useful when:

You want to allocate all scratch space before the sort operation begins

There is not enough space on any single disk for a scratch file

The existing disk space is too fragmented to hold a default scratch file extent

The sort operation requires an initial scratch file that does not fit on one volume
To use a partitioned scratch file, you first use the FUP CREATE command to manually
partition and create the file. The syntax for creating a partitioned scratch file at a TACL
prompt is:
filename
is the name of the file to create. If you specify a partial file name, the TACL
command interpreter uses the current node, volume, and subvolume.
PART
sets options for each partition. Enclose options for each partition with parentheses
and separate them with commas.
partition-num, [\node.]$volume
identifies the partition and specifies a location. Specify an integer from 1 to 15 for
partition-num. Specify a volume for the partition location. You can also specify
a node. However, for optimal performance, locate scratch files on the node where
SORTPROG is running.
pri-extent-size, sec-extent-size
specifies the primary and secondary extent sizes for a partition. The default
primary extent size is one page, or 2048 bytes. If you specify no secondary extent
size or zero extents, sec-extent size defaults to the size of the primary
extent. The value you specify can be in pages, bytes, or megabytes (MB). The
default extent unit is pages. The maximum value is 65,535 pages, or 134 MB.
FUP CREATE filename, PART (partition-num , [\node.]$volume
[,pri-extent-size [, [sec-extent-size ]]]),...